Stacked antenna array for television signal reception



Oct. 13, 1953 H. R. HlLLlSON STACKED ANTENNA ARRAY FOR TELEVISION SIGNALRECEPTION Filed Aug. 15, 1950 Patented Oct. 13, 1953 UNITED STATESPATENT OFFICE STACKED ANTENNA ARRAY FOR TELE- VISION SIGNAL RECEPTION 1Claim.

This invention relates to antenna arrays and more particularly to aselective antenna array for television reception.

It is among the objects of the invention to provide an improved antennaarray which will accurately discriminate between the signals frombroadcast stations located in different directions from the antenna,giving uniform gain to the signals from a selected station and rejectingthe signals from the other station or stations, which will receivesignals on all frequency channels in current use with equaleffectiveness, which has a high front to back reception ratio and highselectivity for different frequency channels, which operates effectivelywith the transmission lines currently in use, and which is mechanicallysimple and economical to manufacture, strong and durable inconstruction, and easy to install and adjust.

Other objects and advantages will become apparent from a considerationof the following description and the appended claim in conjunction withthe accompanying drawing wherein the single figure is a perspective viewof a stacked antenna array illustrative of the invention.

With continued reference to the drawing, the antenna array thereinillustrated comprises an elongated mast I formed of a suitablestructural member, such as a metal tube, and adapted to be mounted inupright or substantially vertical position on a suitable support such asthe building chimney II. 1

A first crossarm I2 is mounted on the mast Ill above the support I I bya suitable sleeve bracket I3 having one sleeve portion slidablyreceiving the mast and another sleeve portion slidably receiving thecrossarm I2 which crossarm may comprise a length of metal tubing ofsuitable length and diameter. The crossarm I2 is disposed substantiallyperpendicular to the mast I0 and projects to opposite sides of the mastfor a purpose to be later explained.

A second crossarm I4 is mounted on the mast above the crossarm I2 by asleeve bracket I5 similar to the sleeve bracket I3 and is disposedsubstantially perpendicular to the mast. The crossarm I4 also extends toopposite sides of the mast and the two crossarms I2 and I! have theirlongitudinal center lines substantially in a common plane which alsoincludes or is parallel to the longitudinal center line of the mast It.

It has been found that for current operating conditions a distance ofapproximately twenty eight inches between the two crossarms givesoptimum operational results.

Each of the crossarms constitutes a component of a separate antennaassembly and the two antenna assemblies carried in vertically spacedapart relationship by the mast II] constitute the antenna array of theinvention.

The lower antenna assembly comprises a refiector I6 mounted on one endof the crossarm I2 by a sleeve bracket I I. This reflector is disposedsubstantially at right angles to the mast m and the crossarm I2 and ismounted on the crossarm at its mid-length location. It may convenientlycomprise a metal rod of approximately one half inch diameter and ninetyfour inches in length.

At the side of the mast remote from the reflector I 6 the crossarm I2carries a low frequency channel dipole, generally indicated at It. Thisdipole I8 comprises two metal rods or bars I9 and 20 disposed in end toend relationship with their adjacent ends spaced apart approximately twoand one half inches and secured in a sleeve bracket 2I of insulatingmaterial mounted on the crossarm I2 at a distance of approximatelytwenty six inches from the reflector I6. Each of the dipole rods or barsI9 and 20 may conveniently comprise a metal rod approximately threeeighths of an inch in diameter and forty one inches long. The dipole I8is substantially parallel to the reflector I6 and substantiallyperpendicular to the crossarm I2 and the'mast I0 and is symmetricallydisposed relative to the crossarm.

A conventional three hundred ohm transmission line 22 extends along themast and is provided at its upper end with two leads 23 and 24 which areconnected to terminals 25 and 26 respectively, carried at therespectively opposite ends of a terminal block 27 of electricallyinsulative material mounted on the mast It between the crossarms I2 and.I4. A conductor 28 leads from the terminal 25 to the dipole element I9and a similar conductor 29 connects the terminal 2'! to the dipoleelement 20, the dipole elements I9 and 20 being thus connected to thetransmission line leads 23 and 24 respectively.

A director 30 is mounted on the crossarm I2 at a location spaced fromthe side of the dipole I8 remote from the reflector I6 and mast It, andis substantially parallel to the dipole I8 and per pendicular to themast IG and crossarm I2. This director 30 may conveniently comprise ametal rod of one half inch diameter and sixty four inches long spacedsix inches from the dipole and symmetrically disposed relative to thecross arms. This director is mounted on the crossarm without electricalinsulation, by suitable means, such as the sleeve bracket 3|, and is notelectrically connected in any way to the transmission line.

A high frequency channel dipole, generally indicated at 32, is mountedon the crossarm at a location spaced from the side of the directorremote from the dipole I8. The dipole 32 comprises two elements 33 and36 in the form of metal rods disposed in end to end relationship withtheir adjacent ends spaced apart a distance of approximately two and onehalf inches. Each of these rod elements may conveniently comprise ametal rod of approximately three eighths inches in diameter andapproximately eighteen inches in length and are received at theiradjacent ends in a sleeve bracket 35 of electrically insulative materialmounted on the crossarm |'2. This second dipole is spaced approximatelythirteen and.

three quarter inches from the director 35 and is substantially parallelto the director 33 and-symmetrically disposed relative to the crossarm|2.

An auxiliary director 68 is: mounted on crossarm |2 between director 33and high frequency channel dipole 32 by a suitablebracket. G1 and issubstantially parallel to the director 38 and, dipole 32. This directoris shorter than director 30 and somewhat longer than dipole 32 and isslight ly closer to the adjacent dipole than to the adjacent director.

A second director 36 is mounted on the end of the crossarm |2 remotefrom the reflector l6 and comprises a metal rod or bar approximately onehalf inch in diameter and twenty four inches long spaced five inchesfrom the side of the dipole 32 remote from the director 30. This seconddirector 35 is substantially parallel to the dipole 32 and symmetricallydisposed relative to the cross- .arm l2.

The reflector IS, the dipole Hi, the directors 30 and 60, the dipole 32and the director 36 all have their longitudinal center linessubstantially in a common plane which plane is substantially coincidentwith the longitudinal center line of the crossarm l2 and which plane issubstantially perpendicular to the longitudinal center linev of the mastHi.

The upper antenna assembly is similar in all respects to the lowerantenna assembly described above and includes a reflector 31 similar indimeter and length to the reflector l6 and mounted on one end of thecrossarm l4 by a sleeve bracket 38 in position directly above andsubstantially parallel to the reflector IS. The upper antenna assemblyfurther includes a low frequency channel dipole, generally indicated at38, a. director 40, a high frequency channel dipole, generally indicatedat 4|, an auxiliary .director 62 between director 40 and dipole 4| and adirector 42 at the side of dipole 4| remote from auxiliary director 62.

The dipole 39 is similar in all respects to the dipole |8 and isdisposed above and substantially parallel to the dipole I8. It includestwo rod elements 43 and 44 disposed in end to end relationship andreceived at their adjacent ends in a. sleeve bracket 45 of insulativematerial mounted on the crossbar l4 at the side of the mast H) remotefrom the reflector 3! and spaced approximately twenty six inches fromthe re flector 31 and substantially parallel to the latter. The dipoleelement 43 is electrically connected. to the terminal 25 by a conductor46 and the element 44 is electrically connected to the terminal 21 by aconductor 41.

The director 40 is mounted on the crossarm H by a sleeve bracket 48 andis disposed directly above and substantially parallel to the director30. It is also substantially parallel to the dipole 33 and spacedapproximately six inches from this dipole at the side of the latterremote from the reflector 31.

The dipole 4| comprises two rod or bar elements 49 and 50 disposed inend to end relationship and received at their adjacent ends in a .sleevebracket 51 of electrically insulative material mounted on the crossarm Mat a location spaced thirteen and three quarter inches from the side ofthe director 40 remote from the dipole 39.

The auxiliary director 62 is parallel to director 40 and dipole 4| andsomewhat nearer the latter than the former. It is shorter than director40 is secured on crossarm l4 by a bracket 63.

A vertically disposed Q bar 52 is electrically connected at its upperend to the dipole element 49 and at its lower end to the dipole element33. A similar Q bar 53 is electrically connected at its upper end to thedipole element 50 of the dipole 5| and at its lower end to the element34 of the dipole 32. A conductor 54 is electrically connected at one endto the Q bar 52 substantially at the mid-length location of this Q barand is electrically connected at its other end to the terminal 26 on theterminal block 21 and a similar conductor 55 is electrically connectedat one end to the Q bar 53 substantially at the mid-length location ofthis Q bar and is electrically connected at its other end to theterminal 25, the conductors 54 and 55 being crossed over or transposedbetween the Q bars and the terminals on the block 21. A collar 55 ofelectrically insulative material surrounds the two conductors 54 and 55at the cross over location to prevent frictional movement of theseconductors relative to each other.

The director 42 is similar to the director 36 and is disposed directlyabove and substantially parallel to the latter. It is substantiallyparallel to the dipole 4| and spaced approximately five inches from theside of this dipole remote from the director 40.

The above described construction provides an antenna array which has ahigh front to back reception ratio so that it will effectivelydiscriminate between signals from broadcasting stations located atdifferent sides of the antenna, pro-- viding a uniform gain for thesignals from a selected brodcast station and rejecting signals from astation located at a diiferent side of the antenna. It is also highlyeffective in rejecting reflected signals, thus avoiding the conditionusually referred to as ghost pictures on the television screen and ishighly selective as to different channel frequencies providing sharp andclear pictures.

While the dimensions as given above have been found to be highlyeffective for broadcast channel frequencies currently in use, it is tobe understood that these dimensions may be varied without in any wayexceeding the scope of the invention.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is, therefore, to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claim rather than by the foregoingdescription, and all changes which come within the meaning and range 01equivalency of the claim are, therefore, intended to be embracedtherein.

What is claimed is:

An antenna array comprising a mast adapted to be mounted insubstantially vertical position, and antenna assemblies carried by saidmast in vertically spaced apart relationship relative to each other,said antenna assembliesbeingsubstantially identical and coextensive andeach comprising a crossarm mounted on said mast and disposedsubstantially perpendicular thereto, a first dipole mounted on saidcrossarm and disposed substantially perpendicular to said crossarm andsaid mast, a reflector longer than said first dipole mounted on saidcrossarm and disposed substantially parallel to said first dipole at alocation spaced from one side of the latter, a first director shorterthan said first dipole mounted on said crossarm substantially parallelto said first dipole and spaced from the other side of the latter, asecond dipole shorter than said first director mounted on said crossarmparallel to said first director and spaced from the side of the latterremote from said first dipole, a second director shorter than saidsecand dipole mounted on said crossarm parallel to said second dipoleand spaced from the side of the latter remote from said first director,a terminal block mounted on said mast between said antenna assemblies,spaced apart terminals carried by said block, electrical conductorsconnecting the first dipoles of both assemblies to said terminals, Qbars interconnecting the second dipoles of both assemblies, andtransversed conductors connecting said Q bars to said terminals.

HAROLD R. HILLISON.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Re. 23,273 Kearse Sept. 25, 1950 2,112,269 Carter Mar. 29,1938 2,248,335 Burkhart July 8, 1941 2,292,791 Mims Aug. 11, 19422,380,519 Green July 31, 1945 OTHER REFERENCES Radio and TelevisionNews, September 1949, page 69.

